Tanning process



' uing liquor formed from Patented May 16, 1933 UNITED STATES PATENTOFFICE Y FREDERICK A. VOGEL, OF MILTON ERNEST, ENGLAND; JESSIE M. VOGELEXECUTRIX. OF

SAID FREDERICK A. VOGEL, DECEASED, ASSIGNOR, BY MESNE .ASSIGNMEN'IS, TOEDWIN B. H. TOWER, JIL, OF MILWAUKEE, WISCONSIN I TANNING PROCESS NoDrawing. Application filed June 10,

The present invention relates to a tanning process such as employed fortanning an animal hide or pelt into leather.

According to the ordinary vegetable or -chrome tanning process employedin practice,

the hide or pelt is prepared or made ready to be tanned by being delimedor bated to eliminate therefrom the lime employed to remove its hair,and then it is subjected to tannage for a prolonged time or period invegetable or chrome tanning liquor to convert or transform its tannablesubstance into complete leather.

The prctannage which has heretofore been proposed in such a process-tolessen the time to produce complete leather has resulted inthe ultimateleather being impaired in quality and unsuitable for ordinary service.

The present invention has for its object to provide a tanning processwhich will tan a hide into leather of the same or better quality in lesstime than the ordinary tanning process.

Another object is to provide a tanning process which will producestrong, pliable, and durable leather in less time than the ordinarytanning process.

Another object is to provide a tanning process which will retain inthehide for trans-' formation into complete leather the tannablesubstance before eliminated and lost in deliming the hide.

Another object is to provide a tanning process which will produce from agiven hid leather of more weight and area.

Another object is to provide a tanning process which will keep the hidein condition to have the tanning agent readily difi'use throughout itsentire tannable substance.

According to this invention as ordinarily practiced, a limcd hide orpelt which has had its surface. lime eliminated or removed is pretannedfor a limited period in a pretanaldehyde, such as formaldehyde, andsulfite cellulose extract to fix or set its tannable substance andcommence transformation thereof into leather, and then the hide thuspretanned int'o partial leather is tanned until its tannable substanceis converted or transformed into complete leather.

1924. Serial No. 719,109. 1

In order to explain the invention further, an example thereof as appliedin practice to vegetable tanning is hereinafter explained.

A limed hide or pelt, which has been dehaired and has .had its surfaceor excess lime removed by lactic acid, is subjected to pretannage foralimited period in a pretanning liquor to set or fix its tannablesubstance and commence rapid transformation thereof into leather.

The pretanning liquor is in essence an aldehyde, such as formaldehyde,and sulfite cellulose extract diluted in Water to a suitable solution. i

The formaldehyde and the sulfite cellulose extract are such asordinarily employed In tanning in other relations, for instance,formalin and spruce extract.

When the hide is subjected to the pretanning liquor the formaldehydewhich is a rapid tanning agent fixes and sets its tannable substance andcommences rapid transformation thereof into leather'and the sulfitecellulose extract which is an acid medium keeps the hide open and incondition to have the pretanning liquor and likewise the subsequentordinary tanning liquor readily diffuse throughout its entire tannablesubstance.

If the pretanning liquor did not have the by increasesthe ultimate yieldof leather from the hide.

'hen the hide has been pretanned for a limited period of about five orsix hours it is then tanned inordinary tanningliquor until its tannablesubstance is converted or transformed into complete leather.

As compared to the ordinary process, the

tanning process herein explained will tan 9.

hide to produce complete leather of equal or better quality in much lesstime and the leather yielded from such hide will have more weight andarea.

The present tanning process as explained herein to exemplify itscharacteristics may be practiced and modified in various ways accordingto the conditions without in any wise departing from the invention asdefined in the hereinafter claims.

The invention set forth in the foregoing specification is hereby claimedas follows: 1. Atanning process, comprising surface deliming a hideafter its hair has been removed by lime, then subjecting the hide for alimited period to pretannage in mixed aldehyde and sulfite celluloseextract to commence transformation of its tannable sub 4 stance intoleather, and thereafter subjecting the hide thus pretanned to tannage ina vegetable tanning liquor for a sufficient period to transform itstannable substance into complete leather.

2. A tanning process, comprising surface deliming a hide after its hairhas been removed by lime, then subjecting the hide for a limited periodof pretannage in mixed formaldehyde and sulfite cellulose extract tocommence transformation of its tannable substance into leather, andthereafter subjecting the hide'thus pretanned to tannage in a vegetabletanning liquor for a suflicient period to transform its tannablesubstance into complete leather.

Signed at the city, county, and State of New York, this 6th day of une,1924.

FREDERICK A. VOGEL.

